Circular knitting machine

ABSTRACT

A multi-feed circular knitting machine having a yarn changing mechanism at each feed. A guide at one of the feeds is threaded up with an elastomeric thread. Knife elements and a suction tube respectively cut and normally hold any yarn withdrawn from knitting. Adjacent the suction tube, between the latter and the cutting point, is a holder device and a trapper component cooperable to hold the elastomeric thread after it is withdrawn but prior to it being cut. In one form, the holder device consists of a spring-biassed stem slidable up and down a tubular support and having a thread-engaging foot for co-operation with the trapper component.

United States Patent Grewcock et a1.

[ 51 June 13, 1972 CIRCULAR KNITTING MACHINE [72] Inventors: Sidney B. Grewcock; Alan Cooper, both of Burbage; Arthur Amos, Barwell; Paul Sylvester, Hinckley, all of England [73] Assignee: Barber & Nicholls Limited, Burbage, Near Hinckley, England [22] Filed: July 6, 1970 [21] Appl. No.: 52,646

[] Foreign Application Priority Data Dec. 18, 1969 Great Britain ..61,795/69 April 16, 1970 Great Britain ..18,151/

[52] US Cl... ..66/l40S [51] Int. Cl. ..D04b 15/61 [58] Field of Search ..66/ S, S, 134, 140R, 66/145 R [5 6] References Cited UNITED STATES PATENTS 3,257,829 6/1966 Parthum ..66/140 S X 3,164,975 1/1965 Haberhauer... .....66/l40 S X 3,379,036 4/1968 Farmer ..66/145 R 2,270,432 1/1942 Fregeolle.... ..66/l34 3,367,146 2/1968 Allred ..66/140 S UX 2,377,729 6/1945 Toone et a1 ..66/134 2,059,076 10/1936 Aaronson ..66/140 R 3,016,725 1/1962 Kimrey et a1... .....66/140 R 3,030,788 4/1962 Peel ..66/ 140 R 3,055,199 9/1962 Stack... ..66/145 R X 1,727,784 9/1929 Pulster ..66/ 140 R FOREIGN PATENTS 0R APPLICATIONS 1,139,539 1/1969 Great Britain ..66/140 S 1,178,213 1/1970 Great Britain ..66/1 34 647,547 10/1962 Italy ....66/14O R 1,179,647 l/l970 Great Britain 66/140 R 288,393 4/1928 Great Britain ..66/134 Primary Examiner-Wm. Carter Reynolds Attorney-Larson, Taylor and Hinds 57] ABSTRACT A multi-feed circular knitting machine having a yarn changing mechanism at each feed. A guide at one of the feeds is threaded up with an elastomeric thread, Knife elements and a suction tube respectively cut and normally hold any yarn withdrawn from knitting. Adjacent the suction tube, between the latter and the cutting point, is a holder device and a trapper component co-operable to hold the elastomeric thread after it is withdrawn but prior to it being cut. In one form, the holder device consists of a spring-biassed stem slidable up and down a tubular support and having a thread-engaging foot for co-operation with the trapper component.

2 Claims, 9 Drawing Figures CIRCULAR KNITTING MACHINE This invention relates to circular knitting machines of the kind having a rotary needle cylinder and including (a) a yarn changing mechanism at at least one feed comprising a group of movable yarn guides selectively operable to feed selected yarns or threads to and withdraw the same from the needles, according to requirements, and (b) a yarn or thread severing and holding, i.e. trapping," mechanism having scissor-like knife elements and a fixed suction tube of a pneumatic system respectively operable to cut and hold a withdrawn yarn or thread until next required.

The invention can be applied to a twin-feed machine with a yarn changing mechanism at at least the main feed. Alternatively, the invention may be applied to a multi-feed machine with a yarn changing mechanism at each and every feed.

Although the invention is not necessarily limited in this respect, it is principally the intention to apply it to a circular hosiery knitting machine of the general kind referred to but also of the particular type equipped not only with a welting dial furnished with a circular series of dial jacks for the production of double or roll-welts, but also with a yarn or thread severing device comprising, in combination, a flat, ring-like saw coupled to and rotatable together with the welting dial, said saw having sharpened saw teeth formed right around its periphery, and a sharpened knife element adapted to seat upon the flat upper surface of the rotary saw and to cooperate with relevant saw teeth in the severance of yarns or threads as and when they are withdrawn from knitting.

Thus, as well known to those skilled in knitting technology, whenever on a hosiery machine of the type just described a double or roll-welt is to be 'made, knitted loops of a course are transferred from the needles to, and temporarily held by, the dial jacks whilst knitting of the welt proceeds, whereupon the held loops are transferred back to the needles to complete the welt of folded febric. Moreover, in such a machine the rotary saw and the knife co-operable therewith are common to both or all of the feeds: thus, whenever a yarn or thread is withdrawn from knitting as a consequence of a selected yam guide, previously in its feeding position, being moved into its non-feeding position, a length of the withdrawn yarn or thread will be automatically caught into a space between two saw teeth and thereby swept by the rotating saw beneath the knife at which point the yarn or thread will be severed by the cooperative scissor-like action of the sharpened edge of the relevant saw tooth and the operative edge of the knife element seated upon it.

The invention is particularly concerned with a method of knitting integrally on to or into a circularly knitted article, or portion of fabric, an elasticated welt, band or segmentincorporating courses or part courses knitted in an elastic or elastomeric thread.

Heretofore, when attempting to do this on many circular knitting machines of the kind herein referred to, the severed end of an elastic or elastomeric thread withdrawn from knitting immediately contracted and as a consequence became too short to be satisfactorily sucked into and held within the pneumatic trapper tube.

Naturally, this disability made it practically impossible to incorporate into circular knitted fabric courses, or part courses, of an elastic or elastomeric thread. The result of this disability was that when it was previously required to provide a circularly knitted article with, say, an elasticated welt it was necessary, as a separate operation, to sew on to the article a portion of separately produced elastic web.

Accordingly, the primary object of the present invention is to provide, in a circular knitting machine of the kind herein referred to, simple, relatively inexpensive and efficient means designed to obviate the foregoing difficulty.

A particular aim is to provide specific practical means for this purpose in a circular hosiery machine either of the general kind or of the particular type hereinbefore described, thereby enabling stockings, tights and similar articles to be produced with integrally knitted elasticated welts, garter bands or panels.

According to this invention there is provided, at a location closely adjacent to the open end of the fixed suction tube, and between the latter and the point where the scissorlike knife elements co-operate to cut a yarn or thread withdrawn from knitting, a holder device and an associated trapper component which are co-operable at predetermined times to positively grip and hold between them, prior to cutting, an elastic or elastomeric thread withdrawn from knitting, the said holder device and trapper component thus constituting an individual elastic or elastomeric thread trapper which is additional to the fixed suction tube, and the arrangement being such that, with the holder device in contact with the trapper component, any yarn withdrawn from knitting (other than an elastic or elastomeric thread) can move freely past the holder device directly into the cutter.

The idea accordingly is that whereas, on the improved machine, any non-elastic yarn will be directly cut and sucked into the suction tube wherein it will be pneumatically held until next required, as is usual in any circular knitting machine of the kind herein referred to, the withdrawal from knitting of an elastic or elastomeric thread will be accompanied by controlling actuation of the holder device to positively grip the said thread between it and the associated trapper component immediately prior to the thread being cut whereby when cutting does take place the severed end of the thread will be prevented from contracting. It is to be clearly understood, however, that when the held elastic or elastomeric thread is cut there will be created a comparatively short end thereof which extends freely from beneath the foot of the holder device and is of a length equal to the distance between the holder device and the scissor-like knife elements; this free or loose end of thread, being very near to the opening into the fixed suction tube, will therefore, be drawn into the latter and held in a controlled fashion until the elastic or elastomeric thread is next required to be fed to the needles. As will accordingly be appreciated, the actual free cut end of an elastic or elastomeric thread withdrawn from knitting is, in fact, pneumatically held and controlled, the holder device simply acting as an auxiliary mechanical trapper to positively grip the thread and prevent it from contracting, when cut. By the adoption of this simple expedient the cut end is prevented from becoming too short to be satisfactorily sucked into and pneumatically held within the suction tube.

In a convenient embodiment of the invention, the thread holder device may be vertically disposed immediately above a trapper component in the form of a stationary end trim plate and consist of a relatively thin stem having at its lower end an enlarged thread-engaging foot, e.g. of truncated conical form. The stem is slidable up and down within a relatively fixed tubular support which is wholly open at its lower end to enable the corresponding end of the stem to extend below the said support.

In order that the invention may be more clearly understood and readily carried into practical effect, specific constructional examples of the thread holding means provided thereby will now be described with reference to the accompanying drawings, wherein,

FIG. 1 is a view principally of the head of an 8-feed circular hosiery machine of the particular type concerned, showing the thread holding means in position thereon and also the part of the control drum of the machine from which the holder device, co-operable with the associated trapper component, is operated,

FIG. 2 is a plan view corresponding to FIG. 1 showing all of the eight feeds, and the control drum (in dotted lines),

FIG. 3 is a side view of the connections through the medium of which the thread holder device is operated at the dictates of the control drum,

FIG. 4 is a vertical sectional view of so much of the head of the knitting machine as is necessary to show the guide or feeder which carries the elastic or elastomeric thread in its out position and the said thread being taken from the needles by the rotary saw, this view also depicting the end trim plate constituting the trapper component, the holder device and the suction tube of the pneumatic system,

FIG. 5 is a plan view corresponding to FIG. 4 showing the elastic or elastomeric thread after it has been gripped between the holder device and the end trim plate FIG. 6 is a general perspective view of the yarn severing and pneumatic holding mechanism, with the thread holder device raised, and the elastic or elastomeric thread, shown withdrawn from knitting and in the course of being carried by the rotating saw towards the relatively stationary knife element seated upon it, ready to be gripped by descent of the said holder device,

FIG. 7 is a view similar to FIG. 6 but illustrating the gripped elastic or elastomeric thread after it has been cut and the free end thereof has been drawn into the suction tube,

FIG. 8 is a detail vertical sectional view of the thread holder device, the stationary knife element and the rotary saw taken on the line VIII VIII of FIG. 5,

FIG. 9 is an exploded view, partly in cross-section, of the welting dial, the rotary saw and the cam ring for the dial jacks all components included in FIG. 8.

Like parts are designated by similar reference characters throughout the drawings.

In FIGS. 1 3, the main frame of the 8-feed circular hosiery knitting machine is designated FR. Within the back part of this frame, below and at the rear of the knitting head Kl-I, is mounted the intermittently rotatable and conventional control drum CD ofthe machine.

The positions of the eight feeds of the machine are indicated at F F*. At each such feed there is provided a yarn or thread changing mechanism of quite usual form comprising a group of individually pivoted yarn or thread guides or feeders 11', 11 and 11 (see FIG. 5), selectively operable from an intermittently turnable drum 12 which is furnished with prearranged selector bits 13. These bits are suitably set out for action selectively upon lugs 14 on the said guides or feeders. As shown in FIGS. 4 and 5, each drum 12 has rigidly secured to it a ratchet wheel 15 co-operable with a pawl 16. This pawl is ivotally mounted upon an actuating lever 17 which in turn rocks freely about the rotational axis of the drum 12. The actuating lever 17 is forked at 17a (FIG. 4) for engagement with a pin 18 on a lever 19 controlled, through the medium of a Bowden cable 20, from the control drum CD. In each of FIGS. 4 and 5, an elastic thread guide or feeder 11 at the second feed F is shown in its out," i.e. non-feeding, position to withdraw the elastic thread ET from knitting. The guide or feeder 11 on the other hand, is shown in its in position feeding a yarn Y to the needles. At each feed, moreover, there is provided a feed plate 21 furnished with pot eyes 22 through which yarns or threads from supply packages are guided.

As regards the knitting head KI-I, this basically comprises a rotary needle cylinder 23 equipped with a circular series of knitting needles 24. Surrounding the upper end of the needle cylinder 23 is a tricked sinker ring 25 equipped with a circular series of outside sinkers such as 26 (see FIG. 4) co-operable with the needles 24. Located concentrically within and at the upper end of the needle cylinder 23 is a conventional welting dial 27 (FIGS. 4 and 8) which is mounted upon a vertical spindle 28 arranged to be motor driven through drive-transmitting means (not shown) housed within an encasement 29.

The yarn severing device with which the illustrated machine is equipped comprises, in combination, a fiat ring-like saw 30 which is mounted upon, coupled to and rotatable together with the welting dial 27 (see FIG. 9), said saw having sharpened saw teeth 30a right around its periphery, and a sharpened knife element 31 which is seated upon the flat upper surface of the rotary saw 30, in the manner depicted in FIGS. 6 and 7, and co-operates with saw teeth in the severance of yarns or threads as and when they are withdrawn from knitting. As will be seen in FIGS. 5 -9 the saw 30 has a vertically disposed annular flange 30b.

The main yarn or thread holding (trapping) component of the mechanism is constituted by a suction tube 32 which may be made of copper and is incorporated in a pneumatic system. The open end 32a of the tube 32 is shaped as shown in FIGS. 5, 6 and 7, its lower edge being spaced a little above and parallel to a fixed horizontal end trim plate 33 of brass. This plate is superimposed upon and attached by screws, to a cam ring 34 by means of which the jacks (not shown) in the welting dial 27 are actuated. The cam ring 34, of stepped formation, is located within the saw and the confines of the vertical annular flange 30b thereof; in fact, the ring 34 constitutes a bearing for the saw. As will be seen in FIG. 9, the underside of the rotary saw 30 is formed with recesses 30c for reception of upward protuberances 27b of the radial trick walls 270 of the welting dial 27. It is in this way that the saw 30 is positively driven by, and in company with, the said dial.

As shown most clearly in FIG. 8, the knife element 31 is pivotally mounted within a forked lower end 35a of a vertically disposed stem 35 which in turn is mounted within a cylindrical portion 36a of a bracket 36. The latter is attached, by means of a screw 37, upon the top ofa carrier 38 which is supported, adjustably, upon the top of a raised or platform portion 33a of the brass end trim plate 33. To prevent any turning movement of the stem 35 it is provided with an outwardly directed pin 39 which is guided in a vertical slot 36b cut in the cylindrical portion 36a of the bracket 36. A compression spring 40 is interposed between the closed upper end of the cylindrical portion 36a and the upper end of the stem 35 to hold the knife element 31 yieldably in contact with the upper surface of the saw 30.

In accordance with the characteristic feature of the present invention, there is provided, closely adjacent to the open lower end 32a of the suction tube 32, and between the latter and the point where the knife element 31 co-operates with a saw tooth 30a to cut a yarn or thread withdrawn from knitting, a holder device, generally designed HD, and an associated trapper component constituted by an opposed portion of the fixed end trim plate 33. The holder device HD and the opposed portion of the plate 33 accordingly provide an elastic thread trapper which is additional to the suction tube 32.

The holder device HD is vertically disposed and consists of a relatively thin stem 41 having at its lower end an enlarged thread-engaging foot 41a of truncated conical form. The stem 41 is slidable up and down within a relatively fixed tubular support 42 which, as shown in FIG. 8, is wholly open at its lower end to enable the lower end of the stem formed with the thread-engaging foot 41a, to extend below the support. The upper end of the tubular support 42 is secured within a hollow bossed portion 43aof a bracket 43. The last mentioned bracket is attached, by means ofa screw 44, upon the top of a lateral extension 38a of the carrier 38. A compression spring 45 (see FIG. 8), interposed between the upper end of the stem 41 and the opposed underside of the mainly closed top of the hollow bossed bracket portion 43a, spring-biasses the stem 41 into its operative position with its enlarged thread-engagin g foot 41a in contact with the end trim plate 33.

The holder device is lowered and raised respectively into and out of contact with the plate 33, at appropriate times, under the control of a cam either on the main control drum or on an auxiliary control drum of the machine, through intermediate connections of any suitable character. For example, and as shown in FIGS. 1 and 3, the upper end of the stem 42 of the holder device HD is attached to one end of a Bowden cable 46 the other end of which is connected to one arm 47a of a pivoted two-armed lever 47 the other arm 47b of which is arranged to be acted upon by a cam 48 on the control drum CD. In this case, the Bowden cable 46 extends upwardly through a hole 43b formed in the otherwise closed upper end of the bossed portion 43a of the bracket 43. The lever 47 is controlled by a tension spring 49.

To enable the thread-engaging foot 41a of the stem 41 to seat with an effective gripping action upon the end trim plate 33, the underside of the foot is as shown in FIG. 8, made concave, thereby leaving only a peripheral edge for line contact with the trim plate.

In any event, it is preferred that the surface of the plate 33 shall, as illustrated be recessed at 33b to receive the foot of the holder device so that the lower margins of this foot, whenever the device is in its down position is sunk somewhat below the surrounding surface of the plate 33. In this way, any one of the non-elastic yarns such as Y, when withdrawn from knitting, is permitted to pass freely over the end trim plate directly into the knife 30a, 31 without any liklihood of being drawn between the underside of the foot and the plate.

If desired, the bottom of the recess 33b in the plate 33 may be covered by a small plastic pad such as 50 with which the footof the holder device makes contact to grip and hold an elastic thread ET withdrawn from knitting.

Assume now that the elastic thread guide or feeder 11 in FIG. 6 has been raised to withdraw from knitting the elastic thread ET: the operation of the machine is then as follows:

First, a length of the elastic thread ET extending from the guide or feeder 11' in its non-feeding position will be caught between two teeth 30a of the ring-like saw 30. At about this same time, the stem 41 of the holder device HD will be automatically raised against the action of its spring 45, at the dictates of the relevant cam such as 48 on the control drum CD. As the engaged length of the thread ET is swept round by the saw towards the knife element 31, it first passes to a position between the underside of the foot 41a of the stem 41 and the recess 33!; in the trim plate 33 below: this position is clearly shown in FIG. 6. At this instant, determined by the control drum CD, the stem 41 is released and moves down under the spring action to firmly grip the elastic thread ET and clamp it between the underside of the foot 41a and the plastic pad 50 in the recess 33b. A portion of the thread ET then extending from the holder device HD is moved beneath the knife element 31 where it is severed, the free, cut end ET being immediately drawn into the fixed suction tube 32 and pneumatically held as illustrated in FIG. 7.

During its withdrawal from knitting and its consequent conveyance, by the saw 30, towards the knife element 31, the elastic thread ET is drawn around pins 51 and 52 which serve to guide it beneath the open lower end of 32a of the suction tube 32: this ensures that upon the thread being cut its free, cut end ET is drawn into instead of missing the said tube.

When the elastic thread is next required to be knitted, the guide or feeder 11 is first moved into its feeding position and, after the thread so introduced to the needles has been taken by a few of the latter and caused to tuck, the stem 41 of the holder device HD is again lifted to release the thread.

The invention makes it possible to produce on the improved machine a tubularly knitted article or fabric having a welt, band or segment which-is elasticised by knitting an elastic or elastomeric yarn into the fabric of the said welt, band or segment in predeteminedly spaced wales of suitably spaced courses, the said thread being floated across those wales in which it is not knitted.

lclaim:

l. A circular knitting machine which includes, in combination, a rotary needle cylinder; needles operable in said cylinder; a yarn changing mechanism at at least one feed comprising a group of movable yarn guides selectively operable to feed selected yarns to and withdraw same from the needles, according to requirements. at least one of the guides being threaded up with an elastomeric thread; and a yarn and thread severing and holding mechanism having scissor-like knife elements and a fixed suction tube of a pneumatic system respectively operable to cut and hold a withdrawn yarn or thread until next required; said machine being characterized in that there is provided, at a location adjacent to an open end of the fixed suction tube, and between the latter and the point where the scissor-like knife elements cooperate to cut a yarn or thread withdrawn from knitting, a stationary trapper component in the form of an end trim plate and an associated holder device vertically disposed above the trapper component, the latter and the holder device being cooperable, at

predetermined times determined by control means, to positively grip and hold between them, immediately prior to cutting, an elastomeric thread withdrawn from knitting, said holder device and trapper component thus constituting an individual mechanical elastomeric thread trapper which is additional to the fixed suction tube, the thread holder device consisting of a stem which, besides having at its lower end an enlarged thread-engaging foot, is slidable up and down within a fixed tubular support whooly open at its lower end to enable the thread engaging foot to extend below the said tubular support, and the surface of the trapper component being recessed to receive the thread-engaging foot so that the lower portion of the foot, whenever said device is in its down position, is sunk below the surrounding surface of the trapper component.

2. A circular knitting machine according to claim 1, wherein the underside of the enlarged thread-engaging foot of the holder device is made concave, thereby leaving only a peripheral edge thereof for line contact with the bottom of the recess in the trapper component. 

1. A circular knitting machine which includes, in combination, a rotary needle cylinder; needles operable in said cylinder; a yarn changing mechanism at at least one feed comprising a group of movable yarn guides selectively operable to feed selected yarns to and withdraw same from the needles, according to requirements, at least one of the guides being threaded up with an elastomeric thread; and a yarn and thread severing and holding mechanism having scissor-like knife elements and a fixed suction tube of a pneumatic system respectively operable to cut and hold a withdrawn yarn or thread until next required; said machine being characterized in that there is provided, at a location adjacent to an open end of the fixed suction tube, and between the latter and the point where the scissor-like knife elements cooperate to cut a yarn or thread withdrawn from knitting, a stationary trapper component in the form of an end trim plate and an associated holder device vertically disposed above the trapper component, the latter and the holder device being cooperable, at predetermined times determined by control means, to positively grip and hold between them, immediately prior to cutting, an elastomeric thread withdrawn from knitting, said holder device and trapper component thus constituting an individual mechanical elastomeric thread trapper which is additional to the fixed suction tube, the thread holder device consisting of a stem which, besides having at its lower end an enlarged threadengaging foot, is slidable up and down within a fixed tubular support whooly open at its lower end to enable the thread engaging foot to extend below the said tubulaR support, and the surface of the trapper component being recessed to receive the thread-engaging foot so that the lower portion of the foot, whenever said device is in its down position, is sunk below the surrounding surface of the trapper component.
 2. A circular knitting machine according to claim 1, wherein the underside of the enlarged thread-engaging foot of the holder device is made concave, thereby leaving only a peripheral edge thereof for line contact with the bottom of the recess in the trapper component. 